Journal of The Japanese Society for Non-Destructive Inspection
Print ISSN : 0367-5866
Volume 62, Issue 9
Displaying 1-1 of 1 articles from this issue
  • Kiyoshi KOYAMA, Hiroshi HOSHIKAWA, Susumu WATANABE
    2013 Volume 62 Issue 9 Pages 469-476
    Published: September 01, 2013
    Released on J-STAGE: September 26, 2013
    JOURNAL FREE ACCESS
    In recent years, not only flaw detection but also accurate estimation of flaw size is demanded in eddy current nondestructive testing. An eddy current testing (ECT) signal varies depending on the depth, length, width and shape of flaw, therefore, this signal includes information on the flaw characteristics. Using this information, many flaw shape estimation techniques have been proposed. Genetic algorithm (GA) has been used as one of these techniques. This paper describes reconstruction of the flaw shape from the ECT signal of a new uniform eddy current probe using GA. The new uniform eddy current probe (new probe) developed by the authors consists of a long and wide tangential exciting coil and a long rectangle detecting coil. The authors propose use of the technique to calculate the flaw signal by superposing the ECT signal, which does not use FEM to calculate the flaw signal of each flaw shape. Under this experimental condition, the authors found the relationship between the signal obtained by the flaw shorter than the detecting coil width of new probe and also longer than the detecting coil width. That is, the ECT signal is calculated by superposing ECT signal of a shorter flaw than the detecting coil width of a new probe. GA is successfully able to estimate the shape of a flaw where it is located within a ±15 mm area parallel to winding from the center of new probe without pinpointing the flaw position.
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